In this case it's more that multiple companies (Apple, Qualcomm, MediaTek and now Xiaomi) have used the same process (N3P) to produce multiple chips with similar performance. Regardless of Moore's Law death that isn't surprising.

That's just punting the meta which is why are companies converging on similar processes? Plausible explanation being that Moore's law exponential is going away.

Moore's law is flattening, however, designs and implementations are often highly inefficient. Just like software often has bloat, so does chip design.

It's already flattening out. The rate of progress is much faster in 90-00s then now.